Bodenstein Sarah, Casas Sandra M, Tiersch Terrence R, Peyre Jerome F La
Aquatic Germplasm and Genetic Resources Center, School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA, United States.
School of Animal Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, United States.
Front Mar Sci. 2023;10. doi: 10.3389/fmars.2023.1194296. Epub 2023 May 17.
Triploid oysters are widely used in off-bottom aquaculture of eastern oysters, . However, farmers of the Gulf of Mexico (GoM) and Atlantic coast estuaries have observed unresolved, late-spring die-offs of triploid oysters, threatening the sustainability of triploid aquaculture. To investigate this, the physiological processes underlying oyster growth (e.g., feeding, respiration) and mortality of one-year-old diploid and triploid oysters were compared in early summer following an uptick in mortality. It was predicted that higher triploid mortality was the result of energetic imbalances (increased metabolic demands and decreased feeding behavior). Oyster clearance rates, percentage of time valves were open, absorption efficiency, oxygen consumption rates (basal and routine), ammonia excretion rate were measured in the laboratory and scope for growth was calculated. In addition, their condition index, gametogenic stage, infection level, and mortality were measured. Mortality of triploids in the laboratory was greater than for diploids, mirroring mortality observed in a related field study. The physiological parameters measured, however, could not explain triploid mortality. Scope for growth, condition index, and clearance rates of triploids were greater than for diploids, suggesting sufficient energy reserves, while all other measurements where similar between the ploidies. It remains to be determined whether mortality could be caused from disruption of energy homeostasis at the cellular level.
三倍体牡蛎被广泛应用于东部牡蛎的垂下式养殖。然而，墨西哥湾（GoM）和大西洋沿岸河口的养殖户观察到三倍体牡蛎在春末出现无法解释的死亡现象，这威胁到了三倍体养殖的可持续性。为了对此进行调查，在死亡率上升后的初夏，对一岁的二倍体和三倍体牡蛎生长（如摄食、呼吸）和死亡的生理过程进行了比较。据预测，三倍体较高的死亡率是能量失衡（代谢需求增加和摄食行为减少）的结果。在实验室中测量了牡蛎的清除率、瓣膜张开时间百分比、吸收效率、耗氧率（基础和常规）、氨排泄率，并计算了生长空间。此外，还测量了它们的状况指数、配子发生阶段、感染水平和死亡率。实验室中三倍体的死亡率高于二倍体，这与相关实地研究中观察到的死亡率情况相符。然而，所测量的生理参数无法解释三倍体的死亡率。三倍体的生长空间、状况指数和清除率高于二倍体，表明有足够的能量储备，而倍性之间的所有其他测量结果相似。细胞水平上能量稳态的破坏是否会导致死亡还有待确定。
